.min{
    display: flex;
    flex-wrap: wrap;
}
.todo{
    width: 400px;
    height: 150px;
    background-color: white;
    margin-right: 20px;
    position: relative;
    padding: 10px;
    box-sizing: border-box;
}
.n3{
    width: 100%;
    margin: 30px 0;
}
.n1{
    display: flex;
    justify-content: space-between;
}
.n2{
    width: 100%;
    height: 35px;
    box-shadow: 0 0 #999 0.3;
}
.n2 ul{
    list-style: none;
    height: 35px;
    width: 100%;
}
.n2 ul li {
    width: 100%;
    height: 35px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2); /* 水平偏移 0, 垂直偏移 2px, 模糊半径 4px, 灰色半透明 */
}